[cfe-commits] r153550 - in /cfe/trunk: include/clang/Driver/CC1Options.td include/clang/Driver/Options.td include/clang/Frontend/CodeGenOptions.h lib/CodeGen/CGExpr.cpp lib/Driver/Tools.cpp lib/Frontend/CompilerInvocation.cpp test/CodeGenCXX/pr12251.cpp
Chandler Carruth
chandlerc at gmail.com
Tue Mar 27 16:58:37 PDT 2012
Author: chandlerc
Date: Tue Mar 27 18:58:37 2012
New Revision: 153550
URL: http://llvm.org/viewvc/llvm-project?rev=153550&view=rev
Log:
Move the emission of strict enum range metadata behind a flag (the same
flag as GCC uses: -fstrict-enums). There is a *lot* of code making
unwarranted assumptions about the underlying type of enums, and it
doesn't seem entirely reasonable to eagerly break all of it.
Much more importantly, the current state of affairs is *very* good at
optimizing based upon this information, which causes failures that are
very distant from the actual enum. Before we push for enabling this by
default, I think we need to implement -fcatch-undefined-behavior support
for instrumenting and trapping whenever we store or load a value outside
of the range. That way we can track down the misbehaving code very
quickly.
I discussed this with Rafael, and currently the only important cases he
is aware of are the bool range-based optimizations which are staying
hard enabled. We've not seen any issue with those either, and they are
much more important for performance.
Modified:
cfe/trunk/include/clang/Driver/CC1Options.td
cfe/trunk/include/clang/Driver/Options.td
cfe/trunk/include/clang/Frontend/CodeGenOptions.h
cfe/trunk/lib/CodeGen/CGExpr.cpp
cfe/trunk/lib/Driver/Tools.cpp
cfe/trunk/lib/Frontend/CompilerInvocation.cpp
cfe/trunk/test/CodeGenCXX/pr12251.cpp
Modified: cfe/trunk/include/clang/Driver/CC1Options.td
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Driver/CC1Options.td?rev=153550&r1=153549&r2=153550&view=diff
==============================================================================
--- cfe/trunk/include/clang/Driver/CC1Options.td (original)
+++ cfe/trunk/include/clang/Driver/CC1Options.td Tue Mar 27 18:58:37 2012
@@ -178,6 +178,9 @@
HelpText<"Place each function in its own section (ELF Only)">;
def fdata_sections : Flag<"-fdata-sections">,
HelpText<"Place each data in its own section (ELF Only)">;
+def fstrict_enums : Flag<"-fstrict-enums">,
+ HelpText<"Enable optimizations based on the strict definition of an enum's "
+ "value range.">;
def ftrap_function_EQ : Joined<"-ftrap-function=">,
HelpText<"Issue call to specified function rather than a trap instruction">;
def funroll_loops : Flag<"-funroll-loops">,
Modified: cfe/trunk/include/clang/Driver/Options.td
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Driver/Options.td?rev=153550&r1=153549&r2=153550&view=diff
==============================================================================
--- cfe/trunk/include/clang/Driver/Options.td (original)
+++ cfe/trunk/include/clang/Driver/Options.td Tue Mar 27 18:58:37 2012
@@ -444,6 +444,7 @@
def fno_spell_checking : Flag<"-fno-spell-checking">, Group<f_Group>;
def fno_stack_protector : Flag<"-fno-stack-protector">, Group<f_Group>;
def fno_strict_aliasing : Flag<"-fno-strict-aliasing">, Group<f_Group>;
+def fno_strict_enums : Flag<"-fno-strict-enums">, Group<f_Group>;
def fno_strict_overflow : Flag<"-fno-strict-overflow">, Group<f_Group>;
def fno_threadsafe_statics : Flag<"-fno-threadsafe-statics">, Group<f_Group>;
def fno_use_cxa_atexit : Flag<"-fno-use-cxa-atexit">, Group<f_Group>;
@@ -515,6 +516,7 @@
def fstack_protector_all : Flag<"-fstack-protector-all">, Group<f_Group>;
def fstack_protector : Flag<"-fstack-protector">, Group<f_Group>;
def fstrict_aliasing : Flag<"-fstrict-aliasing">, Group<f_Group>;
+def fstrict_enums : Flag<"-fstrict-enums">, Group<f_Group>;
def fstrict_overflow : Flag<"-fstrict-overflow">, Group<f_Group>;
def fsyntax_only : Flag<"-fsyntax-only">, Flags<[DriverOption]>;
def ftabstop_EQ : Joined<"-ftabstop=">, Group<f_Group>;
Modified: cfe/trunk/include/clang/Frontend/CodeGenOptions.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Frontend/CodeGenOptions.h?rev=153550&r1=153549&r2=153550&view=diff
==============================================================================
--- cfe/trunk/include/clang/Frontend/CodeGenOptions.h (original)
+++ cfe/trunk/include/clang/Frontend/CodeGenOptions.h Tue Mar 27 18:58:37 2012
@@ -94,6 +94,7 @@
unsigned SaveTempLabels : 1; /// Save temporary labels.
unsigned SimplifyLibCalls : 1; /// Set when -fbuiltin is enabled.
unsigned SoftFloat : 1; /// -soft-float.
+ unsigned StrictEnums : 1; /// Optimize based on strict enum definition.
unsigned TimePasses : 1; /// Set when -ftime-report is enabled.
unsigned UnitAtATime : 1; /// Unused. For mirroring GCC optimization
/// selection.
@@ -205,6 +206,7 @@
SaveTempLabels = 0;
SimplifyLibCalls = 1;
SoftFloat = 0;
+ StrictEnums = 0;
TimePasses = 0;
UnitAtATime = 1;
UnrollLoops = 0;
Modified: cfe/trunk/lib/CodeGen/CGExpr.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGExpr.cpp?rev=153550&r1=153549&r2=153550&view=diff
==============================================================================
--- cfe/trunk/lib/CodeGen/CGExpr.cpp (original)
+++ cfe/trunk/lib/CodeGen/CGExpr.cpp Tue Mar 27 18:58:37 2012
@@ -872,8 +872,9 @@
llvm::MDNode *CodeGenFunction::getRangeForLoadFromType(QualType Ty) {
const EnumType *ET = Ty->getAs<EnumType>();
- bool IsRegularCPlusPlusEnum = getLangOpts().CPlusPlus && ET &&
- !ET->getDecl()->isFixed();
+ bool IsRegularCPlusPlusEnum = (getLangOpts().CPlusPlus && ET &&
+ CGM.getCodeGenOpts().StrictEnums &&
+ !ET->getDecl()->isFixed());
bool IsBool = hasBooleanRepresentation(Ty);
llvm::Type *LTy;
if (!IsBool && !IsRegularCPlusPlusEnum)
Modified: cfe/trunk/lib/Driver/Tools.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Driver/Tools.cpp?rev=153550&r1=153549&r2=153550&view=diff
==============================================================================
--- cfe/trunk/lib/Driver/Tools.cpp (original)
+++ cfe/trunk/lib/Driver/Tools.cpp Tue Mar 27 18:58:37 2012
@@ -1487,6 +1487,9 @@
options::OPT_fno_strict_aliasing,
getToolChain().IsStrictAliasingDefault()))
CmdArgs.push_back("-relaxed-aliasing");
+ if (Args.hasFlag(options::OPT_fstrict_enums, options::OPT_fno_strict_enums,
+ false))
+ CmdArgs.push_back("-fstrict-enums");
if (!Args.hasFlag(options::OPT_foptimize_sibling_calls,
options::OPT_fno_optimize_sibling_calls))
CmdArgs.push_back("-mdisable-tail-calls");
Modified: cfe/trunk/lib/Frontend/CompilerInvocation.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Frontend/CompilerInvocation.cpp?rev=153550&r1=153549&r2=153550&view=diff
==============================================================================
--- cfe/trunk/lib/Frontend/CompilerInvocation.cpp (original)
+++ cfe/trunk/lib/Frontend/CompilerInvocation.cpp Tue Mar 27 18:58:37 2012
@@ -286,6 +286,8 @@
Res.push_back("-fno-dwarf-directory-asm");
if (Opts.SoftFloat)
Res.push_back("-msoft-float");
+ if (Opts.StrictEnums)
+ Res.push_back("-fstrict-enums");
if (Opts.UnwindTables)
Res.push_back("-munwind-tables");
if (Opts.RelocationModel != "pic")
@@ -1135,6 +1137,7 @@
Opts.NoDwarf2CFIAsm = Args.hasArg(OPT_fno_dwarf2_cfi_asm);
Opts.NoDwarfDirectoryAsm = Args.hasArg(OPT_fno_dwarf_directory_asm);
Opts.SoftFloat = Args.hasArg(OPT_msoft_float);
+ Opts.StrictEnums = Args.hasArg(OPT_fstrict_enums);
Opts.UnsafeFPMath = Args.hasArg(OPT_menable_unsafe_fp_math) ||
Args.hasArg(OPT_cl_unsafe_math_optimizations) ||
Args.hasArg(OPT_cl_fast_relaxed_math);
Modified: cfe/trunk/test/CodeGenCXX/pr12251.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGenCXX/pr12251.cpp?rev=153550&r1=153549&r2=153550&view=diff
==============================================================================
--- cfe/trunk/test/CodeGenCXX/pr12251.cpp (original)
+++ cfe/trunk/test/CodeGenCXX/pr12251.cpp Tue Mar 27 18:58:37 2012
@@ -1,4 +1,5 @@
-// RUN: %clang_cc1 %s -emit-llvm -O1 -relaxed-aliasing -std=c++11 -o - | FileCheck %s
+// RUN: %clang_cc1 %s -emit-llvm -O1 -relaxed-aliasing -fstrict-enums -std=c++11 -o - | FileCheck %s
+// RUN: %clang_cc1 %s -emit-llvm -O1 -relaxed-aliasing -std=c++11 -o - | FileCheck --check-prefix=NO-STRICT-ENUMS %s
bool f(bool *x) {
return *x;
@@ -6,6 +7,12 @@
// CHECK: define zeroext i1 @_Z1fPb
// CHECK: load i8* %{{.*}}, align 1, !range !0
+// Only enum-tests follow. Ensure that after the bool test, no further range
+// metadata shows up when strict enums are disabled.
+// NO-STRICT-ENUMS: define zeroext i1 @_Z1fPb
+// NO-STRICT-ENUMS: load i8* %{{.*}}, align 1, !range !0
+// NO-STRICT-ENUMS-NOT: !range
+
enum e1 { };
e1 g1(e1 *x) {
return *x;
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